Essay on the Indian Summer. 147 



icate rays are either reflected back, or absorbed, while the stronger 

 rays of red and orange, all penetrate to the earth's surface, and by 

 their excess tinge surrounding objects with their own color, and es- 

 pecially the lower atmosphere, which reflects and refracts them in 

 every possible direction : much on the principle that to the eye of a 

 person who has descended to a great depth in a diving bell, every 

 thing appears reddish, because nothing but red rays can penetrate 

 the dense medium which is interposed between him and the sun. 

 Again this redness of the air together with the mechanical irritation 

 produced by the denseness of the aerial vapor, excites a painful af- 

 fection of the eyes — this sensation connected with the smoky appear- 

 ance of the sky, induces great numbers of the inhabitants of this coun- 

 try to believe that the Indian summer consists of a smoky state of the 

 air produced by burning the vegetable decidua which are collected 

 together in the fall season for this purpose, or as some will have it 

 the flring of the neighboring mountains. This appearance of ac- 

 tual smoke is however an optical illusion, produced by the fog- 

 gy appearance of the air, and which seems to find confirmation by 

 the great irritation of the visual organs, efiected by the excess of red 

 rays, &;c. 



The increased temperature which accompanies the existence of 

 this hazy weather is referrible to several causes, viz. 



1st. The prevailing wind, which being from a southerly direction 

 is usually warm. 



2d. The heat radiated from the earth's surface is immediately re* 

 turned (on a well known principle) being reflected back by the haze 

 of the atmosphere, while lastly the temperature is further increased 

 by the condensation of both air and moisture during the formation of 

 the foggy stratum. 



We have now hastily explained, or rather touched upon the lead- 

 ing phenomena of the Indian summer, but acknowledge to have writ- 

 ten on this subject, rather with a view to elicit further enquiry from 

 others than to establish any theory of our own ; every phenomenon 

 connected with the earth's atmosphere is highly deserving of our 

 most earnest investigation, for daily observation confirms, that not 

 only the health, but also the moral qualities of our species, are great- 

 ly under the control of its influences. We hope therefore to see this 

 subject taken up by some one whose time and opportunity are 

 less restricted than our own, and whose superior knowledge of the 

 laws which direct and govern our atmosphere, shall enable him to 

 place it on more sure and elevated ground. 



